User Manual of EM730/EM730E Series Inverter
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As shown in Table 12-30, EM730/EM730E series products mainly involve
common
function codes
. For example, 0x03: function code used to read multiple registers or status
: function code used to write a single register or command, 0x10: function code
used to write multiple registers or commands, and 0x08: function code for diagnosis.
In addition, for some specific functions, such as register writing (RAM) without EEPROM
storage, the
user-defined function codes
include 0x41: function code used to write a single
register or command (without saving), and 0x42: function code used to write multiple registers
When the abnormal valid data is received from a device, a related abnormality message
will be returned (see 11.3.7Exception
). The abnormality function code is defined to
distinguish the abnormal data from normal communication data. Corresponding to the normal
request function code, the
abnormality function code = request function code + 0x80
.
Table 12-30 Function Code Definitions of EM730/EM730E series Product
Function
code
Abnormality
function code
Function
03
83
This function code is used to read multiple registers or status
words.
41
C1
This function code is used to write a single register or
command without saving.
42
C2
This function code is used to write multiple registers or
commands without saving.
08
88
This function code is used for diagnosis.
06
86
This function code is used to write a single register or
command.
10
90
This function code is used to write multiple registers or
commands.
PDU parts are detailed in the following sections, depending on various functions.
1.1.1.1
0x03: function code used to read multiple registers or status words
In the remote terminal unit, this function code is used to read the content in the continuous
block of the holding register. The request PDU describes the starting register address and the
number of registers.
